Exile Guo Wengui says he has secrets about China’s powerful, prompting campaign to silence him

BEIJING—Online allegations by an exiled businessman about corrupt ties between China’s political and corporate elites are riveting many Chinese and threaten to intrude on the Communist Party’s plans for a carefully choreographed leadership transition.

Guo Wengui, an up-by-the-bootstraps tycoon who says he has lived in the U.S. since 2015, has said in rambling video interviews and a deluge of Twitter posts that he has detailed...